Venus Express was Europe's first mission to Venus and explored this world for eight years. The mission ended in December 2014 after the spacecraft ran out of propellant. (Without propellant, it is no longer possible to control the attitude and orient Venus Express towards Earth to maintain communications. It is also impossible to raise the altitude further, meaning that the spacecraft will naturally sink deeper into the atmosphere .)

Venus Express had been on an elliptical 24-hour orbit, travelling 41, 011 miles (66,000 km) above the south pole at its furthest point and to within 124 miles (200 km) over the north pole on its closest approach. Venus Express was designed to study the atmosphere of Venus, from the surface to the ionosphere. The mission reused the same design as ESA's Mars Express and used spare parts from other deep space missions.

After arriving at Venus in April 2006, Venus Express logged many firsts. One of the most significant findings were signs that Venus had been volcanically active in the last three million years -- suggesting the planet may still be geologically active.

The orbiter also made extensive meteorological maps of Venus, providing measurements of wind fields and temperatures and the chemical composition of the atmosphere. The spacecraft found a striking double-eyed atmospheric vortex that dominates the south pole. It detected water molecules escaping into space, found concrete evidence for lightning in the Venusian atmosphere and provided infrared glimpses of the hot surface.

Venus Express made use of two instruments originally built as flight spares for Mars Express and Rosetta, as well as two new instruments. It carried the following seven scientific instruments:

UV and IR Spectrometer for solar/stellar occultation and Nadir Observations (SPICAV/SOIR)
SPICAV/SOIR searched for small quantities of water in the atmosphere. It also looked for sulphur compounds and molecular oxygen, and to determine the density and temperature of the atmosphere at 80-180 km altitude.

UV-visible-near-IR imaging spectrometer (VIRTIS)
VIRTIS studied the composition of the lower atmosphere, below the cloud decks at 35-40 km altitude, and tracked the clouds at ultraviolet and infrared wavelengths. This allowed scientists to study the atmospheric dynamics at different altitudes, and to build the first 3D view of the atmospheric structure.

Analyzer of Space Plasma and Energetic Atoms (ASPERA)
ASPERA investigated the interaction between the solar wind and the atmosphere by measuring outflowing particles from the planet's atmosphere and the particles of the solar wind. It studied how molecules and ions escape from the planet.

Venus Radio Science (VeRa)
VeRa used the powerful radio link between the spacecraft and Earth to investigate the conditions in the ionosphere. Scientists also used it to study the mass, density, temperature and pressure of the atmosphere from 35-40 km up to 100 km altitude, and to determine the roughness and electrical properties of the surface. VeRa also allowed the conditions of the solar wind in the inner solar system to be deduced.

Venus Monitoring Camera (VMC)
VMC, a wide-angle multi-channel camera, imaged the planet at near-infrared, ultraviolet and visible wavelengths. It provided global images of the planet, studying the cloud dynamics and imaging the surface. In addition, it assisted in the identification of phenomena seen by other instruments. This was a new instrument.

Magnetometer (MAG)
Venus has no detectable internal magnetic field and the field around the planet is entirely due to the interaction between the solar wind and the atmosphere. MAG studied this process and helped in understanding the effect this has on the atmosphere. It was a new instrument that reused the sensor design from the Rosetta lander.

Venus Express' High Resolution Infrared Fourier Spectrometer (PFS) unfortunately was never operational, owing to a malfunction that could not be fixed by a series of attempts performed in space. The pointing mirror was stuck in its closed position, preventing the spectrometer (which otherwise worked perfectly) from seeing its targets. PFS was meant to measure the temperature of the atmosphere at altitudes of 55-100 km at a very high resolution, and to make composition measurements of the atmosphere. It was also meant to measure the surface temperature and thereby search for volcanic activity. Thanks to careful scientific planning and optimized use of the other instruments, several of the PFS's scientific objectives were achieved.

Venus Express returned the clearest indication yet that Venus is still geologically active.

Venus Express is a virtual twin of Mars Express. However, the engineers modified the spacecraft to withstand the harsh environment around Venus (the spacecraft receives four times the amount of solar radiation as Mars Express).

Venus Express is a thrifty mission. To keep costs low, Venus Express also used spare parts from Mars Express and Rosetta.